Coal

Topic: Energy Resources of India: Conventional and Non-conventional · NCERT: Class 7, Ch 1 "Geographical Diversity of India"; Class 8, Ch 1 "Natural Resources and Their Use"; Class 10, Ch 5 "Minerals and Energy Resources"; Class 12, Ch 5 "Mineral and Energy Resources"

Meaning

Coal is a fossil fuel: a black or brown rock that burns. It forms from swamp plants that died millions of years ago and were buried, pressed and heated until most of what remained was carbon. In India it is burnt mainly in thermal power stations, and its best grade, coking coal, is made into coke for smelting iron ore.

• Coal gives about 55% of India's primary commercial energy (energy bought and sold as fuel). About 72% of India's electricity comes from coal (IMYB 2022) [3].
• It is India's main home-grown fuel, so it matters a great deal for energy security.

Explanation

How coal forms (cause → process → result)

• Cause: plants grow thickly in swamps. When they die, they sink into wet mud with no air, so they do not fully rot.
• Process:
• New layers of mud and sand pile on top. The plant mass is pressed down and buried deeper.
• Deeper down, it is hotter and the pressure is higher. Water and gases are squeezed out, so the share of carbon rises.

• The longer and deeper the burial, the more "mature" the coal becomes. This is called organic maturity (how far heat, pressure and time have changed the plant material) [3].

• Result: the grade of coal depends on how hard it was pressed, how deep it was buried and for how long.

• Sequence: peat → lignite ("brown coal") → sub-bituminous → bituminous ("hard coal") → anthracite [3].

Grades of coal (lowest to highest carbon)

Grade	What it is	Carbon / heat	In India
Peat	Half-rotted swamp plants. The first stage of coal	Low carbon, high moisture, little heat	Not a commercial fuel
Lignite	Soft brown coal, brown to dark black in colour [3]	High moisture, low-to-medium heat	Neyveli (Tamil Nadu), Barmer (Rajasthan), Kutch (Gujarat)
Sub-bituminous	The stage between lignite and bituminous [3]	Medium	—
Bituminous	Formed by deep burial at higher temperatures. The most common commercial coal	High carbon, good heat	Gondwana coalfields
Anthracite	The best hard coal. Burns with almost no smoke	Highest carbon, highest heat	Very little in India, mainly Jammu and Kashmir

Coking and non-coking coal

• Coking coal (metallurgical coal): high-grade bituminous coal. When heated without air, it turns into coke (a hard, porous fuel). Coke is used in blast furnaces (tall furnaces that smelt iron ore into iron).
• Total coking coal: 37,372.98 MT, only about 9.3% of all coal resources [2].
• Split by type: prime coking 5,443.41 MT, medium coking 30,132.09 MT, semi-coking 1,797.48 MT (as on 01.04.2025) [2].

• Why India imports it: there is not enough at home, and home coal is poorer in quality. Coal imports are allowed freely under Open General Licence (no special permit needed) [3]. Much of it comes from Australia.

• Non-coking coal: burnt in thermal power stations (which burn coal to make steam and electricity) and used in cement and sponge-iron plants.

• Gondwana non-coking resources: 3,61,647.82 MT, about 90% of the total (01.04.2025) [2]. (NCERT: about 80% of Indian coal is non-coking.)
• Graded G1–G17 by heat value. Superior grades (G1–G6) total only 40,328.72 MT. Inferior grades (G7–G17) total 2,93,130.31 MT, about 73% of all coal [2].

Ash: the main quality problem

• Ash is the rock and mineral matter left after coal burns. More ash means less heat, more fly-ash waste and more wear on boilers.
• Why Indian coal has so much ash: in the Gondwana basins, river mud and sand settled together with the plant material. That mineral matter stayed in the coal.
• Raw coal sent to washeries (plants that clean coal to remove ash) has 24% to 33% ash [3].
• After washing [3]:
• Washed coal: 19–22% ash
• Middlings (the medium-quality part): 35–40% ash
• Rejects: over 50% ash

Where it occurs

The Gondwana-Tertiary divide

Feature	Gondwana coal	Tertiary coal
Age	About 250–300 million years (Permian period). NCERT Class 10: "a little over 200 million years"	About 15–60 million years. NCERT Class 10: about 55 million years
Share	3,99,020.80 MT, about 99.6% of 4,00,715.45 MT (01.04.2025) [2]. NCERT: about 98%	1,694.65 MT, about 0.4% [2]
Quality	Mostly bituminous. High ash, low sulphur. Holds all of India's coking coal	Low ash and high heat value, but all of it is "high sulphur" [2]. So it cannot be used directly as metallurgical coal [3]
Region	River valleys of the eastern and central Peninsula. A little in Assam and Sikkim [3]	Assam, Arunachal Pradesh, Nagaland, Meghalaya [3], and Kalakot (J&K)

Gondwana coalfields. Gondwanaland was the old southern super-continent that joined India, Africa, Australia, South America and Antarctica. Its coal formed in long, sunken troughs along old river valleys.

• Damodar valley (Jharkhand–West Bengal): Jharia (largest coalfield; coking coal), Raniganj (second largest), Bokaro, Giridih, Karanpura
• Mahanadi valley (Odisha): Talcher and Ib Valley, mined by MCL (Mahanadi Coalfields Ltd) [3]
• Son valley: Singrauli (Madhya Pradesh–Uttar Pradesh border)
• Godavari and Wardha valleys (Telangana, Maharashtra): SCCL in Telangana produces non-coking coal and supplies most of South India's coal users [3]

Coal resources by state, highest first (01.04.2025) [2]:

• Odisha 1,00,975.78 MT > Jharkhand 93,254.06 > Chhattisgarh 85,263.22 > West Bengal 34,386.09 > Madhya Pradesh 33,563.62 > Telangana 23,288.62 > Maharashtra 13,586.70 > Bihar 9,353.44
• The total of 4,00,715.45 MT counts coal down to 1,200 m depth, in seams 0.90 m or thicker. Of this, 2,20,412.35 MT (about 55%) is "measured" (proved by drilling) [2].
• The inventory is prepared by the Geological Survey of India (GSI) using data from CMPDI, MECL, GSI, SCCL and other agencies [2].

Tertiary coalfields (North-East and J&K)

• Meghalaya: Darangiri, Cherrapunji, Mewlong, Langrin
• Upper Assam: Makum, Jaipur, Nazira
• Arunachal Pradesh: Namchik-Namphuk
• Jammu and Kashmir: Kalakot
• Resources: Meghalaya 583.22 MT, Assam 525.01, Nagaland 510.21, Arunachal Pradesh 90.70 [2].
• NEC (North Eastern Coalfields, part of CIL) runs three mines: Tirap, Tikak and Tipong. Tipong is underground; the other two are opencast [3].
• Rat-hole mining (digging tunnels barely wide enough for one person to reach thin seams) is found at Jowai (Jaintia Hills) and Cherrapunjee (East Khasi Hills) in Meghalaya. The National Green Tribunal (NGT) banned it in 2014.

Lignite. Lignite occurs in Tertiary rocks in the south and west of the Peninsula, and also in J&K and Odisha [3]. Total resources are about 47,370.54 MT [2].

• Tamil Nadu 37,523.65 MT (about 79%) > Rajasthan (Barmer, Bikaner) 6,661.17 > Gujarat (Kutch, Bhavnagar) 2,722.05 > Puducherry 416.61 [2]
• Neyveli (Cuddalore district, Tamil Nadu) is the largest lignite deposit in India. The Neyveli Lignite Mine is the largest opencast mine in the country [3].
• NLC India runs three opencast mines at Neyveli and one at Barsingsar (Rajasthan), with a total capacity of 30.60 MTPA [3].

Production and world position

• 2024-25: 1,047.52 MT, 4.98% more than the year before. CIL mined 781.06 MT, SCCL 69.01 MT, and captive and other mines 197.46 MT [2].
• World (2021): China produced about 50% of the world's coal and lignite. India was second at 9.0%, then the USA (7.88%), Indonesia (7.80%) and Australia (6.02%) [3].
• India has mined coal commercially since 1774. Coal mines were nationalised on 01.05.1973 [3].

Don't confuse with

• Lignite vs bituminous coal: lignite is wet, low-carbon brown coal from Tertiary rocks (Neyveli, Barmer). It is burnt at pithead power stations (power plants built at the mine) because it is too bulky to carry far. Bituminous coal is the hard Gondwana coal that is moved long distances by rail.
• Coking vs non-coking coal: coking coal turns into coke for blast furnaces (steel) and is only about 9.3% of resources, mainly at Jharia [2]. Non-coking coal is the bulk, about 90% [2], and it is burnt in thermal power stations.
• Gondwana vs Tertiary coal: Gondwana coal is old, high-ash, low-sulphur and about 99.6% of resources. Tertiary coal is young, low-ash, high-sulphur and only about 0.4% [2][3].
• Anthracite vs bituminous: anthracite has the highest carbon but is rare in India (mainly J&K). Bituminous is the most common commercial coal.

Prelims Hooks

• Grades by carbon, lowest to highest: peat → lignite → sub-bituminous → bituminous → anthracite [3]. Anthracite in India: mainly Jammu and Kashmir.
• Coal resources by state, highest first (01.04.2025): Odisha > Jharkhand > Chhattisgarh > West Bengal > Madhya Pradesh [2]. Jharkhand is not first.
• Trap: North-East Tertiary coal is low-ash and high in heat value, but its high sulphur keeps it from being used directly as metallurgical coal [3].
• Field–state pairs: Darangiri, Mewlong, Langrin → Meghalaya. Makum, Nazira → upper Assam. Namchik-Namphuk → Arunachal Pradesh. Kalakot → J&K. Talcher, Ib Valley → Odisha. Jharia, Bokaro → Jharkhand.
• Lignite: Tamil Nadu holds about 79% of resources [2]. Neyveli (Cuddalore district) is India's largest opencast mine [3].
• Production in 2024-25: 1,047.52 MT, the first year above 1 billion tonnes. CIL mined 781.06 MT of it [2].

Mains Points

• Distribution shapes industry (GS-I): about 99.6% of coal lies in Gondwana basins of the Damodar, Mahanadi, Son and Godavari–Wardha valleys [2][3].
• So: steel and thermal power plants cluster in the Chota Nagpur–Odisha belt.

• Also: the North-West and South depend on coal carried long distances by rail, or on local lignite such as Neyveli and Barmer.

• Large resources, low quality (GS-III): 73% of resources are inferior grades (G7–G17), and coking coal is only about 9.3% [2]. Raw coal ash runs at 24–33% [3].

• So: India imports coking coal for steel, mostly from Australia.

• Response: coal washeries and blending to stretch home supplies [3]. Pithead power (generating at the mine, as at Neyveli) cuts transport costs. Captive mines (mines that supply the owner's own plants) grew 28% in 2024-25 [2].

• Environment and people (GS-III):

• High-sulphur Tertiary coal releases sulphur dioxide, a cause of acid rain.
• Rat-hole mining in Meghalaya floods and collapses, has used child workers, and drains acid water into rivers. This led to the NGT ban of 2014.
• High-ash Gondwana coal leaves huge piles of fly ash.
• These problems explain why India is shifting towards non-fossil capacity, even though coal still makes about 72% of its electricity [3].

Related concepts

• Anthracite
• Bituminous coal
• Coking coal
• Gondwana coal
• Tertiary coal
• Lignite
• Neyveli lignite

Read more

• Coal: formation, grades and the Gondwana-Tertiary divide